In the group Euphausiacea, females either retain mature eggs in a brood pouch until they hatch, or release the eggs directly into the water column. All the species currently being commercially harvested, however, are broadcast spawners (Nicol & Endo, 1997). The focus of our discussion of the reproduction patterns and strategies of euphausiids is on those species that are of commercial interest,...

An experiment was conducted to investigate the annual reproductive cycle of a Korean endemic species, Acheilognathus majusculus, from Jeokseong-myeon located in Seomjin River. The reproductive cycle is examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), the female ovipositor length index (OLI), monthly variation in egg diameter distr...

BACKGROUND It remains unknown if later life breast cancer risk as determined by reproductive history is mediated by postmenopausal breast density and/or sex steroid levels. METHODS Increased breast density is a strong surrogate for future breast cancer risk. A cross-sectional study with a longitudinal follow up for breast health outcomes evaluated women without breast cancer (n = 1,023; 682 =...

In ungulates, males and females have contrasting life histories, as usually only the females raise the young. How reproductive effort in males varies with individual level and population level characteristics has received little attention in the literature. Using published information on direct (weight loss during the rut) and indirect (rutrelated changes in activity budgets, fighting frequency...

HE extent to which reproductive characteristics can be modified by selection Tis of interest in understanding the nature of genetic variation in characteristics closely correlated with fitness. It is also relevant to the question of effecting genetic improvement in an important trait in species producing protein for human food. Different species and races within species have acquired widely dif...

  Background: Reproductive health problems affect youths in all countries. There is an urgent need to enhance youths reproductive health services to provide a healthy life for this group. In this regard, the present study aimed to evaluate the Reproductive Health Peer Education Program based on the opinion of university students.   Methods :This interventional study was conducted in Qazvin Univ...

Reproductive dysfunction and malignancies related to the male gender represent a serious health concern, whose incidence has significantly risen over the past years. Prior to treatment, testicular or prostate cancer patients often display poor semen characteristics similar to subfertile or infertile patients. This fact is underscored by cases where the malignancy is often diagnosed in males who...

STUDY QUESTION Do clinical characteristics of recurrent miscarriage couples with a chromosomal abnormality and who opt for PGD differ from couples that decline PGD after extensive genetic counselling? SUMMARY ANSWER No differences in clinical characteristics are identified between recurrent miscarriage couples carrying a structural chromosomal abnormality who opt for PGD compared with those t...

Bumble bee workers (Bombus bifarius, Hymenoptera: Apidae) exhibit aggression toward one another after the colony begins producing female reproductive offspring (the competition phase). Workers in competition phase colonies must continue to perform in-nest tasks, such as nest thermoregulation, and to forage for food, to rear the reproductives to maturity. Therefore, competition phase workers are...